Winner of the 2009 Manser Medal, the Gap House is a narrow new-build terraced London townhouse, designed by Pitman Tozer.

The house, which is sited on a plot only 2.3m wide within a conservation area in West London, proves that sustainable architecture is achievable without compromise on the tightest of urban sites.

The house incorporates a number of green strategies including passive solar gain, high levels of insulation, a ground coupled heat pump and rainwater harvesting to minimize its carbon footprint. It achieves all of this without compromising design.

All photographs: Nick Kane

With a street frontage of only 8 ft/2.3 m wide the house sits within a narrow slot, originally the side alley and rear garden of an adjoining property. The challenge was how to create a Low Carbon Building and make a comfortable 4-bed family home, maximising light and space within the constraints of a tight and awkward site. The key to achieving a solution where each habitable room has good daylight and feels spacious, even within the narrowest part, was to stack the smaller bedrooms at the front of the house facing the street and to organise the rear in a cascading configuration with the wet rooms and storage occupying the parts of the plan with no natural light. A courtyard at the rear of the site brings light into the ground floor reception space. A central twisting timber stair held as a piece of sculpture off the walls brings daylight deep into the centre of the plan on each floor.The house was designed and built for partner of the practice Luke Tozer and his family and developed by the practice as a case study project allowing the partners to put in to practice new strategies for Carbon reduction and energy generation.

The house is designed to use approximately 30% of the energy of a typical house built to current Building Regulations, with a predicted reduction in heating bills of approx. £500-£800/annum.